Understanding the difference between composer install and composer update is crucial for managing dependencies in PHP projects. While composer install ensures consistency by installing dependencies from composer.lock, composer update fetches the latest versions allowed in composer.json. This blog explains when to use each command and best practices to avoid dependency

Command composer install composer update
Purpose Installs dependencies from composer.lock Updates dependencies to latest versions based on composer.json
When to Use? When setting up a project or ensuring consistent dependencies When you want to update dependencies to newer versions
What Happens? Installs the exact versions specified in composer.lock Updates packages, modifies composer.lock, and installs new versions

Example:

1️⃣ Using composer install

- Suppose composer.lock contains Laravel 9.2.1.

- Running composer install will install exactly Laravel 9.2.1, ensuring all team members use the same version.

2️⃣ Using composer update

- If composer.json has "laravel/framework": "^9.0", it means Laravel 9.0+ is allowed.
- Running composer update will fetch the latest compatible version, e.g., Laravel 9.5.0.
- It updates composer.lock with new versions.

When to Use Which?

✅ Use composer install: Reads composer.lock and installs exactly what's listed. when setting up a project or deploying to production.
✅ Use composer update: Updates the dependencies listed in composer.json, and rewrites composer.lock. It’s used when you want to upgrade packages.

Tip: Always commit composer.lock to version control to avoid unexpected version mismatches in production. 🚀